Polylmeric films and packages produced therefrom

Abstract

Heat sealable polymeric films having a heat sealable surface comprising a blend of at least one polyethylene and a cyclic olefin/ethylene copolymer having a glass transition temperature T g of greater than 30° C. Such films can be used to form packages showing good peelability, usually with evidence of peeling, after heat sealing to various substrates. These packages are of particular use for packaging foodstuffs and medicaments.

1 . A heat sealable polymeric film having a heat sealable surface comprising a blend of at least one polyethylene and a cyclic olefin/ethylene copolymer having a glass transition temperature T g  of greater than 30° C.  
     
     
         2 . A film according to  claim 1 , wherein the copolymer has a glass transition temperature T g  of less than 220° C.  
     
     
         3 . A film according to either of the preceding claims, wherein the copolymer has a glass transition temperature T g  of from 50 to 175° C.  
     
     
         4 . A film according to  claim 3 , wherein the copolymer has a glass transition temperature T g  of from 65 to 150° C.  
     
     
         5 . A film according to any of the preceding claims, wherein the blend comprises from 60 to 90 wt % of polyethylene and from 40 to 10 wt % of the cyclic olefin/ethylene copolymer.  
     
     
         6 . A film according to  claim 5 , wherein the blend comprises from 65 to 85 wt % of polyethylene and from 35 to 15 wt % of the cyclic olefin/ethylene copolymer.  
     
     
         7 . A film according to  claim 6 , wherein the blend comprises from 70 to 80 wt % of polyethylene and from 30 to 20 wt % of the cyclic olefin/ethylene copolymer.  
     
     
         8 . A film according to any of the preceding claims, wherein the cyclic olefin of the cyclic olefin/ethylene copolymer comprises norbornene.  
     
     
         9 . A film according to any of the preceding claims, wherein the polyethylene has a density of from 0.915 g/cm 3  to 0.935 g/cm 3 .  
     
     
         10 . A film according to any of the preceding claims, wherein the heat sealable surface is formed by an outer layer of a multi-layered polymeric film.  
     
     
         11 . A film according to  claim 10 , wherein the multi-layered film has a base layer comprising a polyolefin.  
     
     
         12 . A film according to  claim 11 , wherein the polyolefin comprises a low density polyethylene.  
     
     
         13 . A film according to any of the preceding claims, including a layer of a polymer having high barrier properties to oxygen.  
     
     
         14 . A film according to  claim 13 , wherein the layer having high oxygen barrier properties comprises a nylon.  
     
     
         15 . A peelable open package comprising a film according to any of the preceding claims heat sealed to a coated metal foil, a polymeric film or a non-woven web.